Promisify gm methods?

[miickel]

Is it possible to use a promise-library, such as Bluebird, to promisify gm instance-methods?

  gm(path)
    .identifyAsync(...)
    .writeAsync(...)
    .catch(...);

I have tried using bluebird.promisifyAll, like I usually do:

var gm = Promise.promisifyAll(require('gm'));

// and/or
Promise.promisifyAll(gm.prototype);

But the async methods doesn't seem to stick.

Any suggestions of what I might be doing wrong?

Many thanks

[amelon]

I have the same problem.
I sent an issue to bluebird.

please read petkaantonov/bluebird#335

[vothanhkiet]

I try today and it's work, use suffix Async on gm's methods.

var Promise = require('bluebird');
var gm = require('gm');
Promise.promisifyAll(gm.prototype);
gm('/home/user/Downloads/test.jpg').identifyAsync()
.then(function (ret) {
    console.info(ret);
})
.catch(function (err) {
    console.error(err);
});

[adius]

I think gm should already provide a promise api by default

[amelon]

bluedbird bug is closed (petkaantonov/bluebird#335).

This issue should be closed as well.

[Beats0]

I use async function

const saveWebp = function (fname: string) {
  return new Promise(function (resolve, reject) {
    gm(`/data/public/images/${fname}`)
      .write(`/data/public/images/${fname}.webp`, (err) => {
        if (err) {
          reject(err);
        } else {
          resolve()
        }
      })
  })
}

const uploadFile = async (ctx: Context) => {
  const fname = '1.jpg'
  const webpSrc = `/${fname}.webp`
  await saveWebp(fname)
  ctx.body = {
    type: 'success',
    webpSrc
  }
}

[ahmadawais]

Here's how you can use asyn/await.

// FILE: utils/resize.js
const gm = require('gm').subClass({ imageMagick: true });


const resizeImage = (image, width) => {
	return new Promise(function(resolve, reject) {
		gm(image)
			.resize(width, false)
			.write(image, err => {
				if (err) {
					reject(err);
				} else {
					resolve();
				}
			});
	});
};

const resize = async (images, width, debug) => {
	const promises = images.map(async image => {
		await resizeImage(image, width);
	});
	await Promise.all(promises);
};

module.exports = resize;

// FILE: index.js
// The call Resize.
const resize = require('./utils/resize.js');
await resize(images, 1080, debug);